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Technology: Headstone is no pushover for vandals

By JEREMY WEBB

Outside the civil engineering department at the University of Newcastle
upon Tyne stands the last word in graveyard technology. It is a prototype
headstone designed to deny vandals, and those with more sinister motives,
their pleasure.

For bizarre pastimes, desecrating graves by pushing over tombstones
takes some beating. But it is all too common, and causes immense distress,
says John Knapton, professor of structural engineering at Newcastle University.

Traditionally, a headstone stands on a small granite or marble base.
Two vertical steel pins protrude from the headstone and are cemented into
matching holes in the base. The problem with this arrangement, says Knapton,
is that a sideways force of about 25 kilograms – which a 12-year-old can
easily muster – is enough to topple both stone and base.

In Knapton’s design, which was inspired by a detachable post in a car
park, the base becomes merely a spacer between the headstone and a metal
spike similar to those used to hold fence posts in place. A steel tube extends
from the spike into a vertical hole in the base, where it fits into a second
tube that protrudes from the headstone (See Diagram). Both tubes have horizontal
holes in them which align with a second hole in the base. The mason taps
a tapered rod through these holes to lock all the components together.

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If necessary, the system can be dismantled within a couple of minutes.
At present, if a headstone needs to be removed – to be repaired or for
an additional name to be engraved – the cement holding the pins into either
the stone or the base has to be dislodged by force. With Knapton’s system,
the mason simply pulls out the rod and lifts off the headstone.

Knapton’s team attracted some strange looks when they conducted ‘pushover
tests’ outside the civil engineering building. In the tests, the headstone
was able to resist the combined efforts of two rugby players – a force of
about 150 kilograms.

Though the university bursar was not keen on the idea of headstones
littering the campus, the engineers have been allowed to leave one in place
to see how well it weathers. ‘It’ll be interesting to see if anyone attacks
it,’ says Knapton.